Research On Gelation And Anti-infective Activity Of Antimicrobial Peptides

Bacterial infection has become a worldwide problem,which has seriously affected human health and life.Unreasonable use of antibiotics has led to the formation of drug resistance of pathogenic bacteria,and thus produced a lot of super bacteria,causing a lot of harm,but also led to serious problems such as wound healing of bacterial infection.Conventional antibiotics have been unable to effectively deal with infections caused by drugresistant bacteria,so it is of great significance to develop new antibacterial materials that resist drug-resistant bacteria and do not produce drug resistance.Most natural functional materials in nature are composed of proteins,and it is easy to see protein and antimicrobial peptides in these materials.Antimicrobial peptide materials have the advantages of high biocompatibility,designable structure,and not easily causing bacterial resistance,which can avoid the mechanism related to bacterial resistance.At present,they have been widely used in the treatment of drug-resistant bacterial infections.The research work of this paper mainly includes the following contents:1.Sponge patch based on antimicrobial peptide hydrogel for treating wound infection.Firstly,we successfully synthesized antimicrobial peptide(KF-12)and constructed antimicrobial peptide hydrogel(AKF-12H)with agarose as skeleton matrix and antimicrobial peptide as active ingredient.It was transformed into antibacterial sponge(AKF-12S)by freeze-drying method,and the morphology,composition,porous characteristics,biocompatibility,antibacterial activity,anti-wound infection function and efficacy of promoting wound healing were systematically studied.The experimental results show that it has a good inhibitory effect on both Gram-negative bacteria and Gram-positive bacteria,and the wound closure rate in vivo wound experiment is 96.31%(on the 10 th day),which was consistent with the antibacterial results in vitro.2.Preparation and antibacterial properties of self-assembled nanogel based on antimicrobial peptides.The antimicrobial peptide self-assembled nanogel(FLKF-12)was induced by the interaction between FF sequence in antimicrobial peptide(KF-12)and Fmoc group.The morphology of the nanogel was characterized,and the potential before and after the reaction increased from-62 m V to-45 m V,and the particle size increased obviously.The results of ultraviolet and X-ray photoelectron spectroscopy(XPS)proved that the nanogel was successfully prepared.Then,the antibacterial property of the nanogel was verified,and after incubated with bacteria for 18 h,the inhibition rate on both Gram-negative and Grampositive bacteria reached more than 95%,indicating that the material had broad-spectrum antibacterial property and high antibacterial rate.In addition,the antibacterial mechanism was further explored through the live/dead staining of bacteria.The results showed that the nanogels could damage the bacterial cell membrane to achieve the antibacterial effect.